1. Field of the Invention
The present invention relates to a magnetic memory and a method or driving the magnetic memory. The present invention also relates to a magnetic memory device using the magnetic memory, e.g., a magnetic random access memory (MRAM).
2. Description of the Related Art
A tunnel magnetoresistance (TMR) element includes a tunnel (barrier) layer and a pair of magnetic layers sandwiching the tunnel layer. The TMR element utilizes a spin tunnel effect that depends on a difference in relative angle formed by the magnetization directions of the magnetic layers. A spin valve TMR element includes a pinned layer and a free layer as a pair of magnetic layers. The magnetization of the pinned layer is relatively hard to rotate, and the magnetization of the free layer is relatively easy to rotate. The free layer functions as a memory layer whose magnetization direction is used for recording information.
When an MRAM includes the TMR elements as magnetic memories in matrix form, the following problems are expected to arise with a higher integration density.
1. A reduction in space between the elements causes magnetic crosstalk and thus results in recording errors.
2. A magnetic switching field and a recording current are increased with decreasing size of the magnetic body.
3. The recording current is limited as wiring becomes finer.
4. A rise in resistance due to finer wiring reduces a S/N ratio for reading.
These problems may impede the achievement of an even higher integration density (e.g., Gbit/in2 or more).